To be fair, Pluto had it coming. The word "planet" never had an official definition, and astronomers had always played fast ...

According to Dr. Grundy, Pluto is a planet. "I use the word 'planet' to refer to it, and most of the planetary science community does too," Grundy said. "Pluto's got everything I like in a planet ...

Clyde Tombaugh discovered Pluto in 1930 at Lowell Observatory in Flagstaff. Here's how Pluto won - and lost - its planetary ...

(Correction: An earlier version of this story misstated how far Pluto is from the sun. The correct number is 3.7 billion miles.) What was discovered in Flagstaff, Arizona, and killed off in Prague?

Conveniently, the word also contained Percival Lowell’s initials. And so on May 1, Lowell Observatory announced that Planet X would be named Pluto. But with its peculiar, tilted orbit and ...

The controversy endures over Pluto's true status, but the solar system underdog continues to capture hearts across the globe. Clyde Tombaugh didn't set out to discover Pluto when he sent his ...

Pluto the planet came first ... argues more than 700 other objects could be considered planets depending on how the word is defined. Ultimately the International Astronomical Union, the ...

In other words, it must be round - not lumpy, like many asteroids. 3. It must have "cleared out its neighborhood" by being the dominant gravitational force in its vicinity. Pluto failed to meet ...